The present invention is related to an electrode for implantation into the cochlea in order to establish electrical contact with the acoustic nerves of the human ear, the electrode comprises an insulating support member and supply lines to said nerves. Electrodes of this kind have been discussed by Martin Sonn. The prior art electrodes are disposed to be inserted through an opening to a patient's cochlea, whose internal ear is defective. In order to establish communication substantially in the area of the cochlea, which is relevant to the intelligibility of speech, the electrode is provided with an extension so that it can reach through approximately two of the cochlea's two and a half turns. It has appeared, however, that the purpose has not been attained, in as much as it has certainly been possible to bring the patient to such a condition that she or he could interpret electrical signals supplied through the electrode as being sound but not as being intelligible speech.
The present invention is based on the opinion that this phenomenon is partly due to the circumstance that the prior art electrode, which during the insertion had to be guided in the cochlea by the aid of the walls of the cochlea. During this insertion damage occurred to these walls. This resulted in the circumstance that the electrode, even if the insertion was tolerably successful, would not be able to position itself in the cochlea in such a manner that the supplied signals were conducted selectively to the acoustic nerves for which they were destined for evoking in the brain those impressions which could cause it to percept the electrical signals as communicating, intelligible speech.